[clang-tools-extra] [clangd][modules] Remove the options that is for gcc, make modules work for clangd when using gcc (PR #200001)

[Aleksandr Platonov via cfe-commits]

ArcsinX wrote:

> > I'm not convinced that simply removing these flags would solve the problem. Clangd should be ignoring the flags, so they are noise on top of the behavior of clangd. As such, I would like to see confirmation first that this works without this change.
> 
> I have debugged many times. And have compared the command that clang++ used with that gcc is using. Then I found these options are redundant. In fact, clang++ also removes the mapfile in its commands, for example @CMakeFiles/.../abc.modmap. So what I have changed is meaningful

It looks like we can just create `.clangd` config to remove these flags.
I.e.
```
CompileFlags:
  Remove: [-fmodule*, -fdeps-*]
```

And after that everything seems working fine

However, I also found that seem we don't forward command mangler right to modules dependency scanner, because I see some errors in logs:
```
E[10:34:07.505] Scanning modules dependencies for .../module-import/Use.cc failed: error: unknown argument: '-fmodules-ts'
error: unknown argument: '-fmodule-mapper=CMakeFiles/Use.dir/Use.cc.o.modmap'
error: unknown argument: '-fdeps-format=p1689r5'

E[10:34:07.506] The command line the scanning tool use is: /usr/bin/g++-14 --driver-mode=g++ -O3 -DNDEBUG -std=gnu++20 -fmodules-ts -fmodule-mapper=CMakeFiles/Use.dir/Use.cc.o.modmap -MD -fdeps-format=p1689r
```

https://github.com/llvm/llvm-project/pull/200001